“If you write for dukes, only dukes will understand, but if you write for the dustman, both will understand. Keep it short, keep it simple, write it in language you would use if you were telling your mum or dad.”

So how to justify obsessive reporting that has no apparent financial rationale, and may even be of little interest to the readers? The answer to this question is central to the idea of a newspaper. If journalism is, in some sense, a public service, then an editor has to understand the ethos of public service – something that is of value to a society without necessarily making a direct financial return. This means thinking of this kind of journalism in the same way you might think of a police, ambulance or fire service. You would, as a citizen, expect such services to be run efficiently, but you would not expect them to have to justify themselves on grounds of profit.There is actually a financial benefit to investigations, but it is a long-term one. Readers, on some level, want their newspapers to be brave, serious, campaigning and dogged. They like corruption to be exposed, overweening power to be challenged, and serious scandals to be unearthed. It reminds them what journalism is for. They admire it. They are even willing to pay for it.A newspaper that consistently breaks investigative stories will (with apologies to those who hate the word) build a brand. The Harold Evans Sunday Times was certainly a “brand”. To this day, it is regarded as one of the high-water marks of challenging 20th-century journalism. Brands have value. A paper that stands for nothing will soon lose its sheen, and then its point, and then its readers. But that’s not always an immediately winning argument if the financials are looking tense and you have impatient investors.